Pathogenetic insight and prognostic information from standard and molecular cytogenetic studies in the BCR-ABL-negative myeloproliferative neoplasms (MPNs).

The frequency of cytogenetic abnormalities in the Philadelphia-negative myeloproliferative neoplasms (MPNs) varies from approximately 30% in primary myelofibrosis (PMF) to less than 5% in essential thrombocytosis (ET). The spectrum of aberrations is heterogeneous, ranging from gains and losses of genetic material to structural changes including unbalanced translocations. However, no specific abnormality has been identified to date. Nevertheless, such investigations can provide evidence of clonality and, as a result, cytogenetic findings have been included in the WHO diagnostic criteria for this group of diseases. The aim of the current review is to discuss the pathogenetic insight and prognostic information that standard, as well as molecular cytogenetic analysis has provided. A brief overview is given of the cytogenetic findings in the individual diseases, followed by a more detailed discussion of the possible pathogenetic consequences of specific abnormalities and their impact on prognosis.